1. Field
The present invention relates to a lens for a light-emitting device and a method of manufacturing a light-emitting device package and, more particularly, to a lens for a light-emitting device usable in a display apparatus or a lighting apparatus, and a method of manufacturing a light-emitting device package.
2. Description of the Related Art
A light-emitting diode (LED) refers a type of semiconductor element capable of displaying light of various colors by forming a light-emitting source using a PN diode of a compound semiconductor. The LED has a long life, a small size, and a small weight, and can be driven using a low voltage. In addition, the LED is durable against impact and vibration, does not require preheating or complicated driving, and is mountable on a substrate or a lead frame in various forms before packaging. As such, the LED may be modularized for various purposes and used in a backlight unit or a variety of lighting apparatuses.
The LED is mounted on the surface of a circuit board and used in a variety of electronic devices. In this case, a lens may be mounted on the LED to diffuse light emitted from the LED.
In general, a lens used in a direct backlight unit may have a hemispherical light-emitting portion, and a sharp concave recess may be provided at the center of the lens to induce light emitted through the light-emitting portion, toward side directions.
However, according to the conventional lens having the sharp concave recess, the amount of light is excessively reduced at the center and light refracted by a spherical surface having a certain curvature is totally reflected and emitted without being sufficiently scattered. As such, a dark ring or a bright ring is generated and thus the uniformity of light is reduced.
In addition, the conventional lens has a simply flat or large-gridded bottom surface. However, in this case, light is easily lost through the bottom surface and thus the efficiency of light is greatly reduced.